Method and apparatus for treating venous insufficiency using directionally applied energy

ABSTRACT

A catheter introduces electrodes in a vein for a minimally invasive treatment of venous insufficiency by the application of energy to cause selective heating of the vein. The catheter is positioned within the vein to be treated, and the electrodes on the catheter are moved toward one side of the vein. RF energy is applied in a directional manner from the electrodes at the working end of the catheter to cause localized heating and corresponding shrinkage of the adjacent venous tissue, which may include commissures, leaflets and ostia. Fluoroscopy or ultrasound may be used to detect shrinkage of the vein. After treating one section of the vein, the catheter can be repositioned to place the electrodes to treat different sections of the vein until all desired venous valves are repaired and rendered functionally competent.

This application is a continuation-in-part of application Ser. No.08/610,911, filed on Mar. 5, 1996, and Ser. No. 08/717,994 filed on Sep.26, 1996, and Ser. No. 08/720,209 filed on Sep. 26, 1996.

BACKGROUND OF THE INVENTION

The invention relates generally to the treatment and correction ofvenous insufficiency, and more particularly, to a minimally invasiveprocedure and apparatus using a catheter-based system having anenergy-delivery arrangement for providing energy intraluminally toshrink a vein to change the fluid flow dynamics, and to restore thecompetency of venous valves thereby restoring the proper function of thevein.

The human venous system of the lower limbs consists essentially of thesuperficial venous system and the deep venous system with perforatingveins connecting the two systems. The superficial system includes thelong or great saphenous vein and the short saphenous vein. The deepvenous system includes the anterior and posterior tibial veins whichunite to form the popliteal vein, which in turn becomes the femoral veinwhen joined by the short saphenous vein.

The venous systems contain numerous one-way valves for directing bloodflow back to the heart. Venous valves are usually bicuspid valves, witheach cusp forming a sack or reservoir for blood which, under retrogradeblood pressure, forces the free surfaces of the cusps together toprevent retrograde flow of the blood and allows only antegrade bloodflow to the heart. When an incompetent valve is in the flow path, thevalve is unable to close because the cusps do not form a proper seal andretrograde flow of blood cannot be stopped.

Incompetence in the venous system can result from vein dilation.Separation of the cusps of the venous valve at the commissure may occuras a result, thereby leading to incompetence. Another cause of valvularincompetence occurs when the leaflets are loose and floppy. Looseleaflets of the venous valve results in redundancy which allows theleaflets to fold on themselves and leave the valve open. The looseleaflets may prolapse, which can allow reflux of blood in the vein. Whenthe venous valve fails, there is an increased strain and pressure on thelower venous sections and overlying tissues, sometimes leading toadditional valvular failure. Two venous conditions which often involvevein dilation are varicose veins and more symptomatic chronic venousinsufficiency.

The varicose vein condition includes dilatation and tortuosity of thesuperficial veins of the lower limbs, resulting in unsightlydiscoloration, pain, swelling, and possibly ulceration. Varicose veinsoften involve incompetence of one or more venous valves, which allowreflux of blood within the superficial system. This can also worsen deepvenous reflux and perforator reflux. Current treatments include surgicalprocedures such as vein stripping, ligation, and occasionally, veinsegment transplant, venous valvuloplasty, and the implantation ofvarious prosthetic devices. The removal of varicose veins from the bodycan be a tedious, time-consuming procedure having a painful and slowhealing process. In addition, patients with varicose veins may undergoinjection sclerotherapy, or removal of vein segments. Complications,scarring, and the loss of the vein for future cardiac and other by-passprocedures may also result. Along with the complications and risks ofinvasive surgery, varicose veins may persist or recur, particularly whenthe valvular problem is not corrected. Due to the long, technicallydemanding nature of the surgical valve reconstruction procedure,treating multiple venous sections with surgical venous valve repair israrely performed. Thus, a complete treatment of all importantincompetent valves is impractical.

Non-obstructive chronic venous insufficiency (CVI) is a problem causedby degenerative weakness in the vein valve segment, or by hydrodynamicforces acting on the tissues of the body, especially the legs, anklesand feet. As the valves in the veins fail, the hydrostatic pressureincreases on the next venous valves down, causing those veins to dilate.As this continues, more venous valves will eventually fail. As theyfail, the effective height of the column of blood above the feet andankles grows, and the weight and hydrostatic pressure exerted on thetissues of the ankle and foot increases. When the weight of that columnreaches a critical point as a result of the valve failures, ulcerationsof the ankle begin to form, which start deep and eventually come to thesurface. These ulcerations do not heal easily because of poor venouscirculation due to valvular incompetence in the deep venous system andother vein systems.

Chronic venous insufficiency often consists of hypertension of the lowerlimb in the deep, perforating and often superficial veins, and mayresult in discoloration, pain, swelling and ulceration. Existingtreatments for chronic venous insufficiency are often less than ideal.These treatments include the elevation of the legs, compressing theveins externally with elastic support hose, perforator ligation,surgical valve repair, and grafting vein sections with healthy valvesfrom the arm into the leg. These methods have variable effectiveness.Moreover, invasive surgery has its associated complications with risk tolife and expense. Similarly, the palliative therapies require majorlifestyle changes for the patient. For example, the ulcers may recurunless the patient continues to elevate the legs and use pressuregradient stockings for long continuous periods of time.

Due to the time-consuming and invasive nature of the current surgicaltreatments, such as valvuloplasty or vein segment grafting, typicallyonly one valve is treated during any single procedure. This greatlylimits the ability of the physician to fully treat patients sufferingfrom chronic venous insufficiency. Every instance of invasive surgery,however, has its associated complications with morbidity and expense.

Another type of treatment, the ligation of vascular lumina bycauterization or coagulation using electrical energy from an electrode,has been employed as an alternative to the surgical removal ofsuperficial and perforator veins. However, such ligation procedures alsoclose off the lumen, essentially destroying its functional capability.For example, it is known to introduce an electrode into the leg of apatient, and position the electrode adjacent the exterior of thevaricose veins to be treated. Through a small stab incision, a probe isforced through the subcutaneous layer between the fascia and the skin,and then to the various veins to be destroyed. A monopolar electrode atthe outer end of the probe is placed adjacent the varicose vein and thereturn electrode is placed on the skin. Once properly positioned, analternating current of 500 kiloHertz is applied to destroy the adjacentvaricose veins by electrocoagulation. The coagulated veins lose thefunction of allowing blood to flow through, and are no longer of use.For example, occluding or ligating the saphenous vein would render thatvein unavailable for harvesting in other surgical procedures such ascoronary by-pass operations.

An approach used to shrink a dilated vein involves the insertion of acatheter that provides RF or other energy to the vein tissue. The amountof energy imparted is controlled so that shrinkage occurs as desired.However, one such device is substantially omni-directional in nature anddoes not permit the application of energy to only a selected portion ofthe vein. The directional application of energy from such a catheter toaffect only a selected portion of the tissue would be particularlyuseful in the case where one desires to shrink only the valvecommissures and not the remainder of the vein, as an example.

Thus a need exists in the art to treat dilated veins, such as thoseresulting in varicose veins or from venous insufficiency, to maintainthe patency of the veins for venous function, and to restore incompetentvalves to valvular competency. Those skilled in the art have recognizeda need to be able to provide energy directionally so that only selectedportions of tissue are affected. The invention fulfills these needs andothers.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the present invention provides aminimally invasive method and apparatus for solving the underlyingproblems of venous insufficiency and uses a novel repair system,including a directional energy delivery catheter for applying energy toa selected tissue site. A method for venous repair comprises the stepsof introducing a catheter having a working end and means for applyingenergy located at the working end to a treatment site in the vein lumen;positioning the means for heating adjacent the treatment site in thevein lumen; directionally emitting energy from the means for heating toselectively heat the treatment site and cause shrinkage of venous tissueat the treatment site; and terminating the emission of energy from themeans for heating after sufficient shrinkage to restore vein competency.An apparatus for applying energy to cause shrinkage of a vein comprisesa catheter having a shaft, an outer diameter and a working end, whereinthe outer diameter of the catheter is less than the outer diameter ofthe vein; and an energy delivery apparatus located at the working end toimpart energy to the venous tissue. In one aspect, the energy deliveryapparatus comprises at least two electrodes located at the working endof the catheter, wherein the electrodes produce an RF field todirectionally heat a venous treatment area adjacent the electrode tocause preferential shrinkage of the vein. The energy is applied to aselected circumferential portion of the vein to achieve a reduction ofthe diameter of the vein.

In another aspect of the invention, an optical energy source may be usedto impart directional energy to selectively heat venous tissue.

An aspect of the present invention is to provide an apparatus and methodfor restoring valvular competence by selectively shrinking the otherwisedilated lumen of the vein by directionally applying energy to tissue.

Another aspect of the present invention is to provide an apparatus andmethod for controllably shrinking loose, floppy valve leaflets inincompetent valves by directionally applying energy in order to restorevalvular competence.

Another aspect of the present invention is to provide an apparatus andmethod which can treat multiple venous sites in a single procedure.

An additional aspect of the present invention is that no foreign objectsor prothesis remain in the vasculature after treatment.

These and other aspects and advantages of the present invention willbecome apparent from the following more detailed description, when takenin conjunction with the accompanying drawings which illustrate, by wayof example, the preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of venous insufficiency in a lower limbshowing both dilatation of the vein and multiple incompetent valveswhich is to be treated in accordance with the present invention;

FIG. 2 is a representative view of a venous section having anincompetent valve taken along lines 2--2 of FIG. 1 which is beingtreated at one commissure by a catheter having an electrode pair, inaccordance with aspects of the present invention;

FIG. 3 is a representative view of the venous section shown in FIG. 2which is being treated at the opposite commissure by the sameelectrode-pair catheter, in accordance with aspects of the presentinvention;

FIG. 4 is a cross-sectional view of treatment of the leaflets of thevalve of FIGS. 2 and 3 in accordance with aspects of the presentinvention;

FIG. 5 is a cross-sectional view of the valve of FIGS. 2, 3 and 4 aftersuccessful treatment showing that it is once again competent;

FIG. 6 is a partial cross-sectional plan view of an embodiment of thecatheter having an electrode pair and incorporating aspects of thepresent invention;

FIG. 7 is a cross-sectional view of the embodiment of the catheterincorporating aspects of the invention of FIG. 6 taken along lines 7--7;

FIG. 8 is an end view of the embodiment of the catheter of FIG. 6 inaccordance with aspects of the invention;

FIG. 9 is an end view of another embodiment of a catheter in accordancewith aspects of the present invention;

FIG. 10 is yet another view of another embodiment of a catheter havingtwo electrodes in accordance with aspects of the present invention;

FIG. 11 is a diagram of a directional RF energy system with a catheterhaving deployable electrodes for directionally imparting energy to avein;

FIG. 12 is an enlarged side view of the working end of the embodiment ofthe directional catheter shown in FIG. 11 showing the bowableelectrodes, temperature sensors, guide wire, and stop surfacearrangement, in accordance with aspects of the present invention;

FIG. 13 is a partial cross-sectional view of a bowable electrode of thecatheter taken across lines 13--13 in FIG. 12 in accordance with aspectsof the present invention;

FIG. 14 is a schematic view of mounting deployable discrete electrodepairs so that they remain the same distance apart when they have beenexpanded;

FIG. 15 is a flux diagram showing the arrangement of discrete electrodepairs to achieve directionality and also shows the primary flux linesresulting from the arrangement;

FIG. 16 is a representative side view of a valve of a venous sectionbeing treated by the embodiment of the catheter of FIG. 11 in accordancewith aspects of the present invention;

FIG. 17 is a front cross-sectional view of the commissures of the venoussection being treated by the embodiment of the catheter of FIG. 11 inaccordance with aspects of the present invention;

FIG. 18 is a front cross-sectional view of the leaflets of the valve ofthe venous section being treated by the embodiment of the catheter ofFIG. 11 in accordance with aspects of the present invention;

FIG. 19 is a side view of another embodiment of a catheter having onepair of bowable electrodes in accordance with aspects of the presentinvention;

FIG. 20 is a side view of another embodiment of a catheter having aballoon formed on the catheter shaft opposite one pair of electrodes inaccordance with aspects of the present invention;

FIG. 21 is a representative view of a venous section having anincompetent valve which is being treated at one commissure by a catheterhaving an electrode pair (not shown) and an inflated balloon oppositethe electrode pair to position the electrode pair in apposition with thecommissure, in accordance with aspects of the present invention;

FIG. 22 is a view similar to FIG. 21 showing the electrode pair of thecatheter of FIG. 21 positioned in apposition with the oppositecommissure by the inflated balloon, in accordance with aspects of thepresent invention;

FIG. 23 is a cross-sectional view of treatment of a leaflet of the valveof FIGS. 21 and 22 in accordance with aspects of the present inventionwhere the balloon has once again been inflated to position the electrodepair as desired;

FIG. 24 is a view of a competent valve resulting from the activity shownin FIGS. 21 through 23; and

FIG. 25 is a view of an alternate embodiment of a directional catheterin which optical energy is directionally applied to the vein wall tocause shrinkage.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to the drawings with more particularity, the invention isembodied in a system and method for the intravenous treatment of veinsusing a catheter to deliver an energy-application element, such as apair of electrodes, to a venous treatment site. Although described asapplying RF energy from the electrode, it is to be understood that otherforms of energy such as microwaves, ultrasound, direct current,circulating heated fluid, optical energy, radiant light, and LASERs maybe used, and that the thermal energy generated from a resistive coil orcurie point element may be used as well. As used herein, like referencenumerals will designate corresponding or similar elements in the variousembodiments of the present invention to be discussed. In addition,unless otherwise noted, the term "working end" will refer to thedirection toward the treatment site in the patient, and the term"connecting" end will refer to the direction away from the treatmentsite in the patient. The following embodiments are directed to thetreatment of the venous system of the lower limbs. It is to beunderstood, however, that the invention is not limited thereto and canbe employed intraluminally to treat veins in other areas of the bodysuch as hemorrhoids, esophageal varices, and venous-drainage-impotenceof the penis.

A partial cross-sectional view of a dilated vein 10 from a lower limbhaving incompetent valves is shown in FIG. 1. These veins are oftendisposed within muscle tissue. Veins have bicuspid valves, and in anormal and competent valve 12, as shown in the upper part of the vein,each cusp forms a sack or reservoir 14 for blood which, under pressure,forces the free edges of the cusps together to prevent retrograde flowof the blood and allow only antegrade flow to the heart. The arrow 16leading out the top of the vein represents the antegrade flow of bloodback to the heart. The venous valves prevent retrograde flow as blood ispushed forward through the vein lumen and back to the heart.

When an incompetent valve 18, such as those shown in the lower part ofthe vein, encounters retrograde flow, the valve is unable to close, thecusps do not seal properly, and retrograde flow of blood may occur.Incompetent valves may result from the stretching of dilated veins. Asthe valves fail, increased pressure is imposed on the lower veins andthe lower valves of the vein, which in turn exacerbates the failure ofthese lower valves. The valve cusps can experience separation at thecommissure due to the thinning and stretching of the vein wall at thecusps. Valves can also become incompetent as a result of loose, floppyvalve leaflets that can prolapse in response to retrograde blood flow orhigh proximal venous pressure.

A method of minimally invasive treatment of venous insufficiency andvalvular incompetency includes utilizing a catheter to deliver bipolarelectrodes to a venous treatment site. A cross-sectional perspectiveview of a dilated vein taken along lines 2--2 of FIG. 1 is illustratedin FIG. 2. The electrodes directionally provide RF energy at the workingend of the catheter to heat and shrink selected venous tissue betweenthe electrodes. The directional application of RF energy in effect formsa heating zone along a portion of the catheter, and allows for localizedor preferential heating of venous tissue so that shrinkage of the venoustissue can be limited to selected areas of the vein, such as thecommissures of venous valves to restore venous valvular competency. Forexample, the venous tissue at the commissures can be heated, and theresulting shrinkage can bring the cusps of the venous valve closertogether to restore competency. Further shrinkage of the cusps andleaflets can be achieved, if necessary, by moving or rotating thecatheter and applying RF energy directionally to the leaflets to causelocalized preferential heating and shrinking of the valve leaflets. Theoutcome of this directional application of RF energy is similar ineffect to surgically placing reefing sutures into a floppy valve leafletduring venous valvuloplasty surgery.

Selectively heating a circumferential portion of the vein results incontrolled shrinkage of the vein while avoiding the application ofenergy to the entire vein wall. By the method and apparatus disclosed,the entire vein wall need not be subjected to heating energy, yetshrinkage of the vein diameter can be effected.

An embodiment of the catheter 20 having a working end 22 having a pairof electrodes for 24 and 26 causing localized heating of the surroundingvenous tissue and shrinkage of the vein is illustrated in FIGS. 2through 6. This and other embodiments of the catheter 20 will bedescribed in greater detail later. The working end 22 includeselectrodes 24 and 26 for providing RF energy to form a localized heatingzone in the tissue at and between the electrodes. The electrodes 24 and26 can be conductive strips, plates, or wires embedded in the workingend 22 of the catheter. RF energy conducted between the electrodes 24and 26 through contacting venous tissue causes that tissue andsurrounding adjacent venous tissue to be heated and shrink. The RFenergy is directional between the electrodes of the catheter, and can bedirectionally applied to the surrounding venous tissue, including thecommissures, cusp and leaflets of the venous valves, or to a specificradial arc of the vein wall.

The method of the present invention for the minimally invasive treatmentof venous insufficiency preferably uses RF electrodes and a deliverycatheter to restore the competency of a vein. Alternatively, the methodis contemplated to be used with any suitable appliance for directionallyapplying radiant energy or heat in the repair or reconfiguration ofincompetent veins. The electrodes for generating the heating effect forshrinking the surrounding venous tissue can be introduced eitherantegrade or retrograde. Particular discussion will be made of thetreatment of varicose veins in the legs, though the method is wellsuited to treating veins in other areas of the body.

When treating the veins of the lower limbs, the patient is typicallyplaced onto a procedure table with the feet dependent in order to fillthe veins of the leg. The leg of the patient is prepped with antisepticsolution. A percutaneous introducer is inserted into the vein using acommon Seldinger technique to access the saphenous or deep vein system.Alternatively, a venous cut-down can be used to access the vein systemto be treated. The procedure for the repair of incompetent veins can beaccomplished by a qualified physician with or without fluoroscopic orultrasonic observation, or under direct visualization. Further, thephysician could palpate the treatment area to determine the location ofthe catheter, and the treatment site, during the procedure when treatingthe superficial venous system. The physician may also palpate the veininto apposition with the electrodes to achieve good contact between theelectrodes and the vein wall.

The delivery catheter 20 could be passed within the vein after insertionthrough the skin. Alternatively, a guide wire for the catheter can beinserted into the vein. The wire is advanced antegrade to the level ofthe most proximal incompetent vein valve which is to be repaired. Thedelivery catheter is then inserted upon the wire and is fed up the legthrough the vein to the level of the dilated venous section to betreated. Fluoroscopy, ultrasound, or an angioscopic imaging technique isthen used to direct the specific placement of the catheter and confirmthe position within the vein. Contrast material can be injected throughor around the catheter to identify the incompetent venous sections to berepaired. A retrograde venogram can be performed in some cases to betterlocalize the treatment site and effect.

From the antegrade approach, the catheter can be placed adjacent theincompetent valve of the vein to be treated. As shown in FIG. 2, thecatheter 20 travels to a venous valve, and is positioned so that theelectrodes can treat specific portions of the vein. The catheter 20 canbe manipulated or torqued so that the working end 22 of the catheter ispositioned to one side of the valve along the commissure. Alternatively,the catheter can include cables, an inflating balloon, or bowablemembers which can selectively move the catheter to one side in order toproperly position the working end of the catheter against selectedvenous tissue.

When the electrodes 24 and 26 of the catheter 20 are positioned at thetreatment site of the incompetent venous section, an RF generator,electrically connected to the electrodes, is activated to providesuitable RF energy, preferably at a selected frequency from a range of250 kHz to 350 mHz. One suitable frequency is 510 kHz. One criterionused in selecting the frequency of the energy to be applied is thecontrol desired over the spread, including the depth, of the thermaleffect in the venous tissue. Another criterion is compatibility withfilter circuits for eliminating RF noise from thermocouple signals.

The RF energy is converted within the adjacent venous tissue into heat,and this thermal effect causes the venous tissue to shrink. Theshrinkage is due to structural transfiguration of the collagen fibers inthe vein. The collagen fibrils shorten and thicken in cross-section inresponse to the heat from the thermal effect. Although the collagenbecomes more compacted during this process, it still retains someelasticity. When RF energy is applied to the venous tissue at and aroundthe incompetent valve of the dilated vein, the shrinkage of the venoustissue at the commissures can restore valvular competency by reducingthe dilation which is preventing the proper functioning of the venousvalve. RF energy is directionally applied to treat one commissure 28, asshown in FIG. 2. The catheter is then moved to treat the commissure 30on the opposite side of the vein, as shown in FIG. 3.

Gross shrinkage of the vein diameter or shrinkage of the venous tissueat the commissures 28 and 30 can restore competency to the venous valve,where the valve leaflets 32 are brought closer together. If the valveshould remain incompetent, and continue to close improperly withprolapsing leaflets 32, manipulating and rotating the working end 22 ofthe catheter 20 for the further application of RF energy to the leaflets32 of the venous valve, as shown in FIG. 4, can shrink the otherwisestretched and prolapsing leaflets 32 of the incompetent valve to restorevalve competency if necessary. Where the leaflets 32 remain apart,energy applied directly to the leaflets of near the leaflets may causethem to move closer together. An approach is shown in FIG. 4 whereenergy is applied to the edges of the leaflets to cause them to movecloser together. Applying energy to the edges of the leaflets ispreferred over applying energy directly to the centers of the leaflets.However, energy can also be applied to the centers.

Preferentially shrinking the venous tissue in and around the venousvalve is shown in the front diagrammatic, cross-sectional views of FIGS.2 through 5. Competency, as shown in FIG. 5, of the valve is restored bythis process. A deflection means such as a bowable member or balloon orother means may be mounted on one side of the distal end of the catheterand deployed to selectively position the catheter at the site.Alternatively, other means may be used to selectively position thecatheter distal end, such as a steering cable or cables.

In FIGS. 2 and 3, a catheter 20 having electrodes 24 and 26 only on oneside is shown. This is the preferred arrangement so that the possibilityof heating the blood is reduced. Such a catheter, and a positioningdevice, is shown in FIGS. 19 and 20, discussed later. The catheter 20shown in FIG. 4 on the other hand has electrodes 25 and 27 that extendover opposite sides of the catheter shaft at the working end 22. Thishas the advantage of allowing the application of energy to both leafletedges simultaneously.

Vein dilation is reduced after RF energy applied from the electrodesheats the surrounding venous tissue to cause shrinkage. RF energy is nolonger applied after there has been sufficient shrinkage of the vein toalleviate the dilation of the vein near the valves, so as to restorevenous function or valvular competency. Sufficient shrinkage can bedetected by fluoroscopy, external ultrasound scanning, intravascularultrasound scanning, direct visualization using an angioscope, or anyother suitable method. For example, the catheter 20 can be configured todeliver an x-ray contrast medium to allow visualization by fluoroscopyfor assessing the condition of the vein and the relationship of thecatheter to the treatment area of the vein during the shrinkage process.As an alternative to fluoroscopy, external ultrasound techniques such asB-scanning using distinct ultrasound signals from different angles, orintravascular ultrasound can be used to acquire a more multidimensionalview of the vein shrinkage at the treatment site. An angioscope can alsobe used to directly visualize and determine the extent and degree ofvein shrinkage.

After treatment, the commissures and the cusps of the venous valvesshould be closer together with little separation or prolapse, and arestoration of the competency of the valve is achieved. Valvularcompetence can be determined by contrast injection or Doppler probemeasurement.

Substantial shrinkage may occur very rapidly, depending upon thespecific treatment conditions. Because the shrinkage can proceed at arather rapid rate, the RF energy is preferably applied at low powerlevels. The properties of the treatment site, such as temperature, canbe monitored to provide feedback control for the RF energy in order tominimize coagulation. Other techniques such as impedance monitoring, andultrasonic pulse echoing, can be utilized in an automated system whichshuts down the application of RF energy from the electrodes to thevenous section when sufficient shrinkage of the vein is detected and toavoid overheating or coagulation in the vein. Monitoring these values inan automatic feedback control system for the RF energy can also be usedto control the spread, including the depth, of the heating effect. Inall instances, the application of RF energy is controlled so as toshrink the venous tissue sufficiently to restore the competency of thevenous valve.

After treating the first venous section shown, the catheter 20 is movedto the next venous valve suffering from insufficiency. The catheter 20can be repositioned to treat as many venous sections and valves asnecessary. RF energy is applied to each venous section to be repaired,until all of the desired venous sections are repaired and the valves arerendered competent. Multiple incompetent valves and dilated venoussections can be treated and repaired in a single minimally invasiveprocedure. If desired, a second introducer can be inserted into the limbof a patient in order to access either the deep or the superficial veinsystem, whichever has yet to be treated. The catheter can then be usedto treat incompetent venous sections in the other vein system.

Where the catheter includes a fluid delivery lumen, such as a guide wirelumen through which cooling fluid may be introduced, the cooling fluidcan be delivered to the bloodstream during RF heating of the vein beingtreated. The delivered cooling fluid reduces any heating effect on theblood, and reduces the risk of heating the blood to the point ofcoagulation. The fluid may also be delivered through ports formed alongthe side of the catheter near the working end and the electrodes (notshown).

After completing the RF procedure for each selected venous section, thecatheter and electrodes are removed from the vasculature. The accesspoint of the vein would be sutured closed if a cutdown had beenperformed, or local pressure would be applied after percutaneous sheathremoval until bleeding was controlled. A bandage would then be applied.A pressure dressing may be necessary. Elastic pressure gradientstockings may be worn subsequently.

As an alternative to the antegrade approach, the catheter can deliverthe electrodes to the venous treatment site from a retrograde approach.The catheter is introduced into a percutaneous sheath that has beeninserted through the skin and into the vein in a retrograde direction.The electrodes at the working end of the catheter are advanced untilcontact with the cusp of the venous valve is observed by fluoroscopy,ultrasound, or other detection method. The catheter is then pulled backslightly to allow treatment of the dilated valve sinus or leaflets inthe vein. The catheter is capable of being deflected, torqued, orotherwise moved to allow for proper placement of the electrodes.Manipulating the working end of the catheter enables preferentialheating along the vein being treated, where the electrodes are placedcloser to one side of the vein wall, such as the commissure. Theelectrodes are activated to deliver RF energy to the venous tissue andshrink the vein. Placing the electrodes in close apposition to thecommissures of the venous valve to cause local or preferential shrinkagenear the commissures can remedy separation of the commissures from veindilation and restore venous function and valvular competency. Aftertreating one end of the valvular commissure, the catheter can then betorqued to place the electrodes near the commissure at the opposite endof the valve. After the venous tissue at the commissures are shrunk, andthe procedure can be repeated for the valve leaflets if necessary.

A partial cross-sectional plan view of an embodiment of a catheter 34 isshown in FIG. 6. The tip of the working end 36 of the catheter can beformed from polymers or other non-conductive materials. Both electrodes38 and 40 are preferably made from stainless steel. In one embodiment,the electrodes may take the form of electrode plates as shown in FIG. 7,which is a cross-sectional view taken along lines 7--7 of FIG. 6. Theelectrodes can be flush with or protrude slightly from the surface ofthe non-conductive working end of the catheter. Further, the electrodescan be slightly recessed at the front tip of the working end so as tominimize the formation of an RF field in front of the catheter.

In another embodiment, the electrodes can be wires located along orembedded in the surface of the working end 36 as shown in FIG. 10. Inthis embodiment, the wires generate heat when suitable energy isapplied. For example, the wires may be formed of a resistive materialand heat up when electricity is conducted through them.

An end view of the working end of the bipolar electrode catheter 34 isshown in FIG. 8. The electrodes are connected to an RF generator so thatthey have opposite polarity. Therefore, current will flow between themthrough contacting venous tissue. This arrangement results in adirectional application of energy localizing the energy along a portionof the catheter at the working end. The port 42 at the working end canprovide cooling fluid or contrast injections to the vein duringtreatment.

The working end 36 of the catheter 34 is rounded to provide anatraumatic tip for the catheter as it is manipulated within the veinlumen. The outer diameter (O.D.) of the working end, in this case, isslightly larger than the dimensions of the catheter shaft 44.Alternatively, the working end 36 of the catheter 34 can have a muchenlarged dimension to form a bulbous shape which limits the amount ofvein shrinkage around the working end. Different sized working ends andelectrodes can be manufactured separately from the catheter shaft 44 forlater assembly with the shaft 44 of the catheter so that a singlecatheter shaft 44 can be used with working ends having a variety ofdiameters. A working end having a specific size or shape could then beused with the catheter depending on the size and type of vein beingtreated. For example, certain larger veins may have a diameter of sevento fifteen millimeters (mm), while other veins may only have a diameterof three to five mm.

The catheter 34 includes a stranded, twisted center conductor 46surrounded by a layer of insulation 48 (FIG. 7) which is preferablyformed from TFE Teflon®. A silver coated copper braid 50 surrounds theinsulated center conductor, and provides flexible and torqueablecharacteristics to the catheter shaft 44. A sheath 52 covers the copperbraid 50, and is preferably made of an electrically resistive,biocompatible material with a low coefficient of friction such asTeflon®. The center conductor 46 is connected to a power source such asan RF generator, to provide RF energy to the electrodes 38 and 40. Thepower source can be controlled by a microprocessor in response toexternal commands or to data from a sensor located at the venoustreatment site such as the temperature sensor 54 shown in FIG. 8. Oneelectrode plate 38 can be in electrical connection with the centerconductor 20 of the RF generator thus giving that electrode a "+"polarity. The other electrode plate 40 is connected to ground throughthe outer braid 50 thereby giving it a "-" polarity. The temperaturesensor 54 is located between the electrodes 38 and 40. Other sensors maybe used and may be mounted in other locations.

The catheter shaft 44 and electrodes 38 and 40 should be constructedfrom materials that would allow their visualization under fluoroscopy,X-ray, ultrasound or other imaging techniques. Preferably, shrinkage ofthe vein is detected by fluoroscopy or external ultrasound techniques.For example, a contrast medium can be injected into the vein to assessthe condition of the vein and the relationship of the catheter to thetreatment area of the vein by phlebography during the shrinkage process.The catheter 34 can also be configured to deliver x-ray contrastmaterial. Alternatively, external ultrasound techniques such asB-scanning using distinct ultrasound signals from different angles toacquire a more multidimensional view of the vein shrinkage at thetreatment site, which improves the detection of uneven shrinkage in thevein lumen than would otherwise be obtainable from a simpletwo-dimensional approach, can be used to assess vein shrinkage. Further,the multi-dimensional approach can assist in orienting the working endof the catheter in directionally applying RF energy to selected portionsof the vein and venous valve. An angioscope can also be used to directlyvisualize the catheter, its position and orientation, and determine thedegree of vein shrinkage.

As mentioned above, other techniques such as temperature monitoring,impedance monitoring, and ultrasonic pulse echoing, may be suitable foran automated system which shuts down or regulates the application of RFenergy from the electrodes to the venous section when sufficientshrinkage of the vein is detected or to avoid charring or coagulation inthe vein.

In one embodiment, the sensing element 54 comprises a temperature sensorsuch as a thermistor or a thermocouple. The temperature sensor can beincluded on the catheter near the electrodes on the working end tomonitor the temperature surrounding the electrodes and the venoussection being treated. A temperature sensor placed between theelectrodes can provide a measure of vein tissue temperature. Monitoringthe temperature of the vein tissue can provide a good indication of whenshrinkage of the vein tissue is ready to begin. The collagen fibrils ofvein tissue shrink at approximately 70° centigrade (C) or higher.Furthermore, monitoring a thermocouple temperature sensor placed on theelectrode facing the vein wall can also provide an indication for whenshrinkage occurs (i.e., 70° C. or higher) and when significant amountsof heat-induced coagulum form on the electrodes (i.e., 85° C.).Therefore maintaining the temperature between 70° to 85° degreescentigrade will produce a therapeutic shrinkage of the vein withoutforming significant amounts of coagulum. Application of RF energy fromthe electrodes is halted or reduced when the monitored temperaturereaches or exceeds the specific temperature at which venous tissuebegins to shrink. The signals from the temperature sensor can be inputto a microprocessor which controls the magnitude of RF energy to theelectrodes in accordance with the monitored temperature FIG. 11).

Instead of a temperature sensing element, another embodiment includesultrasonic piezoelectric elements which emit pulsed ultrasound waves.The piezoelectric elements are operated in pulse-echo fashion to measurethe distance to the vein wall from the catheter shaft. Again, thesignals representative of the pulse-echo would be input to themicroprocessor or to a monitor to allow for manual control, and theapplication of RF energy would be controlled accordingly.

FIG. 9 is an end view of an alternate embodiment of the catheter 34having two pairs of discrete electrodes 58 at the working end Oneelectrode from each pair is connected to a center conductor attached tothe positive terminal from a bipolar RF generator. The other electrodefrom each pair is connected to the metal braid of the catheter which isattached to the negative terminal of the bipolar RF generator. Thepositive electrode of one pair is located adjacent the positiveelectrode of the other pair, as are the negative electrodes. Thisarrangement results in a directional application of RF energy from thecatheter as RF current will flow primarily between electrodes ofopposite polarity in the pairs of electrodes. Thus each electrode inFIG. 9 has two adjacent electrodes, one of like polarity and one ofunlike polarity. The adjacent electrode of unlike polarity is of thesame pair and the adjacent electrode like polarity is of the nextadjacent pair. Current will therefore flow primarily along the fluxlines 56 shown. A temperature sensor 54 is preferably located betweenthe electrodes of unlike polarity. Where there is a central lumen 42that can accommodate fluid delivery or a guide wire, the RF power leadsare wound around the lumen liner made of HDPE or other polymers. Thetemperature sensor leads (not shown) run the length of the catheter to athermocouple 54 located between the electrodes.

In FIG. 9, the electrodes are formed of metallic strips disposed on theouter surface of the distal tip or working end of the catheter. Inanother embodiment, the electrodes may be thicker and may be embedded inthe distal tip. Additionally, more pairs of electrodes may be addeddepending on their size.

FIG. 10 presents yet another embodiment of the working end of a catheterwhere the electrodes comprise wires 60 (only one is shown) that areexposed for conducting RF energy to venous tissue. One wire would beconnected to the RF generator to have a positive polarity while theother wire would be connected to the opposite or negative polarity. Asshown in this embodiment, the center conductor 62 is wound around theguide wire lumen 42.

Another embodiment of the catheter including bowable electrodes disposedon the working end to cause localized heating of the surrounding venoustissue through the directional application of energy is shown in FIGS.11 and 12. The catheter 64 includes four conductive elongate members 66or arms (three can be seen) that can be bent or bowed outward. Theelongate members 66 are surrounded by insulation, except for an exposedarea that serves as the electrode 68 (shown in FIG. 12). Electrodes 68that can be controllably moved outwardly from the catheter by these arms66 will be referred to as bowable electrodes 66. The bowable electrodes66 are formed along the circumference of the catheter 64, but are notfixed to the catheter. Bowing the electrodes outwardly also puts theelectrodes in apposition with the venous tissue to be treated, andconsistent contact of the electrode with the venous tissue can bemaintained. The bowable electrodes preferably expand out to treat veinsup to fifteen mm.

The bowable electrodes 66 are connected to a slidable tube 70 and afixed tip 72 at the working end 74, where moving the tube 70 controlsthe diameter of the electrode deployment for proper treatment of veinlumen having different diameters. The inner stop tube 78 is connected tothe slidable tube 70 and acts as a stop device as the slidable tube 70and inner stop tube 78 are slid over the inner shaft 83 by makingcontact with the stop surface 80 that is fixed in position with the tip.The inner stop tube 78 thus interacts with the stop surface 80 to limitthe amount of deployment of the bowable electrodes 66. A fluid cover 82,shown here in cutaway form as a bellows, prevents fluids from enteringthe space between the inner shaft 83 and the inner stop tube 78 and isdiscussed in greater detail below. A guide wire 98 is seen protrudingout the working end 74.

As shown in FIG. 11, the bowable electrodes are connected to an RFgenerator 84. Also connected to the RF generator is a microprocessor 86.Each bowable electrode in this embodiment has a thermocouple temperaturesensor 88 mounted at the electrode surface 68. Signals from the sensors88 are coupled to the microprocessor 86 which compares them to athreshold temperature or temperatures to determine if RF energy to theelectrodes should be interrupted or should be continued. Themicroprocessor 86 controls the RF generator 84 accordingly.

The catheter itself is fit through a suitably sized sheath for theprocedure. For example, a seven French sheath, which has about a 2.3 mmdiameter, may be used. The sheath is composed of a biocompatiblematerial with a low coefficient of friction. The working end 74 of thecatheter includes a tip 72 that is attached to one end of eachelectrode, and the other end of each electrode is connected to thesliding outer tube 70 formed along the exterior of the catheter shaft.The outer tube 70 extends down the length of the catheter to allow thephysician to directly and mechanically control the effective electrodediameter during the application of RF energy. As the outer slidable tube70 is moved towards and away from the working end in response to thecontrol actuator 76, the electrodes 66 are urged radially outward andinward, respectively. The tip 72 essentially remains stationary whilethe outer tube is moved. Moving the outer tube 70 back toward theconnecting end of the catheter pulls back and flattens the electrodesagainst the catheter before insertion or withdrawal from the vein.Moving the outer tube 70 forward toward the working end 74 of thecatheter causes the electrodes to deflect and radially bow outward to anincreased diameter. The contact area 68 of the electrodes is bowedoutwardly as the opposite ends of the longitudinal electrode are movedcloser together. The outer sleeve may be moved a preset distance tocause the electrodes to bow outwardly to a known diameter. Bowing theelectrodes outwardly also places the electrodes in apposition with thevenous tissue to be treated. By manipulating the slidable outer sleeveto adjust the effective diameter of the catheter defined by the radialbowing of the electrodes, contact between the electrodes and the venoustissue can be maintained during shrinkage.

The control actuator 76 is a switch, lever, threaded control knob, orany other suitable mechanism, preferably one that can provide finecontrol over the movement of the outer tube. By using the controlactuator to move the tube, the effective diameter of the electrode canbe controlled for treating vein lumina having different diameters, andfor providing varying degrees of vein shrinkage. In another embodiment,a movable tip is connected to the actuator 76 by a control wire runningthrough the catheter, so that the movable tip can be manually controlledby the actuator located at the connecting end of the catheter to causethe electrodes 66 to deploy or to contract.

The distal tip 72 is shown to have a nosecone shape, but can have othershapes that allow tracking of the catheter over the guide wire andthrough bends in the venous vascular system. The nosecone-shaped tip 72can be fabricated from a polymer having a soft durometer, such as 70Shore A. Alternatively, the tip can be constructed from a spring coveredwith a thin layer of polyethylene shrink tubing.

The bowable electrodes 66 can be bowed radially outward to treatspecific sections or areas in the vein. As RF energy is applied to thebipolar electrodes, a discrete RF field is created around a portion ofthe catheter as defined by each active pair of the bowed electrodes. TheRF field is directed toward specific venous tissue to be treated. Thevenous tissue becomes heated and begins to shrink. The extent of venousshrinkage is monitored by fluoroscopy, or any other suitable method.After sufficient shrinking the venous tissue has occurred, theapplication of RF energy from the electrodes 66 is ceased.

In order to prevent contamination from blood seeping back through thecatheter, as shown in FIG. 12, a cover 82 is placed over the cathetershaft between the mounts for the bowable members and the stop devices 78and 80. As the outer tube 70 slides over the catheter shaft, the cover82 prevents blood from seeping back through the interface between thesetwo catheter components. The cover is preferably manufactured from aflexible polymer such as a low density polyethylene. The cover 82comprises accordion pleats taking the form of a bellows in oneembodiment to allow the cover to expand and contract as the outer sleeveis moved to expand or retract the bowable electrodes 66, but may alsotake other forms such as a polymer tube. As the outer tube 70 is movedaway from the tip 72, the electrodes are retracted towards the catheterby the bowable members, and the pleated folds of the cover 82 flattenout. As the outer tube 70 is moved toward the tip, the pleated foldswould move closer together.

Turning now to FIGS. 12 and 13, the electrodes 66 may be fabricated fromspring steel, stainless steel, or nitinol so that the electrodes 66would be biased to return to a reduced diameter profile. The electrodesin one embodiment comprise flat strips to facilitate flexing of thecatheter at the working end while being delivered through the bands oftenuous venous vasculature. The strips have relatively large flatsurfaces for contacting the vein wall can be used. Such rectangularwires can have widths ranging from 0.005 to 0.05 inches, and preferablybetween 0.015 and 0.030 inches, to allow four or more electrodes aroundthe catheter shaft. Rounded wires may also be used with a diameterpreferably between about 0.005 to 0.015 inches (about 0.12 to 0.35 mm),but can be up to about 0.03 inches (about 0.7 mm).

The entire length of the bowable longitudinal electrode is conductive,and insulation 90 may be provided over the majority of the electrodesurface in order to prevent any unintended heating effects. Only amodest portion of the conductive surface 68 is exposed to act as theelectrode. The exposed surface can be placed closer to the tip 72 sothat when the bowable electrodes are moved away from the catheter, theexposed conductive surface of the electrodes will be near the tip 72which can be positioned adjacent the commissures and leaflets of thevein. The heating effect is greatest when the electrodes are closetogether since the electrical field density (power density) is greatestat this point. The ends of the electrodes are insulated from each otherto prevent creating larger electrical field densities at the ends,especially as the effective diameter increases which would create evengreater field disparities between the ends and the bowed midsectionwhere the electrode gap is larger. The insulation 90 can be polyimide,paralyene, or another type of insulating film. Insulation 90 providedalong the inner radius of the bowable electrodes away from the venoustissue further prevents heating the blood flowing in the vein andreduces the likelihood of coagulation. The remaining exposed area 68 ofthe electrode is preferably the area which contacts the venous tissueduring apposition. The heating effect is then focused along that portionof the venous tissue and between the positive and negative electrodes.Where the arm 66 has a rectangular shape, then the exposed area whichfunctionally acts as the electrode would then occupy only one face ofthat wire. The insulation 90 surrounding the electrode can further coverthe peripheral edges of the exposed face of the electrode to furtherisolate the blood flow from unintended heating effects.

A sensor 88 such as a small thermocouple for measuring temperature isattached to the electrode 66. As shown in the cross-sectional view ofFIG. 13 taken along lines 13--13 of FIG. 12, the temperature sensor 88is soldered in place through a hole in the electrode so that the sensoris nearly or substantially flush with the exposed surface of theelectrode. The sensor can accurately sense the temperature of the veinwall in apposition with the exposed electrode surface. The leads 92 tothe sensor are situated on the opposite side of the electrode which isinsulated.

As the electrodes are bowed outwardly toward the dilated diameter of thevaricose vein, the gap between electrodes may increase which can weakenthe RF field formed between the electrodes. Maintaining a constant gapor distance between the relevant electrodes of opposite polarity wouldallow a uniform RF field to be applied throughout the procedure as thevein diameter shrinks. Having a uniform RF field regardless of thediameter defined by the bowed out electrodes would also increase thepredictability of the shrinkage. For the directional application of RFenergy, one embodiment would have the bowable members containing theelectrodes mounted on a rectangular or squarish mounting surface, asshown in FIG. 14. The electrodes 94 would lie roughly along the sameplane, and would generally remain the same distance apart as theelectrodes are moved outwardly by the parallel bowable members along thesame plane. Preferably, a 1.0 to 1.5 mm gap is maintained between theelectrodes forming the directional RF field.

FIG. 15 is an end schematic view of the working end of thebowable-electrode catheter 64 and the bowable electrodes 66 of FIGS. 11,12 and 13. In the four-electrode configuration, a preferred embodimentis to have the two pairs of bowable electrodes 66 spaced apart along thecircumference of the catheter to form discrete pairs of electrodes. Eachelectrode would have the opposite polarity from one of its adjacentelectrodes and the same polarity as the other adjacent electrode.Electrodes of opposite polarity would form active electrode pairs toproduce an RF field 96 between them. Thus, discrete RF fields 96 wouldbe set up along the circumference of the catheter. In anotherembodiment, if the adjacent electrodes 66 all had opposite polarities toone another, but were moved closer together to form discrete electrodepairs, two opposite pairs of active electrodes would be formed along thecircumference of the catheter. While an RF field would be formed alongthe entire circumference of the catheter, the RF field would bestrongest between the closely adjacent electrodes in each pair ofopposite electrodes. As a result, heating and shrinkage would beconcentrated between the electrodes of opposite polarity with a smallinter-electrode gap.

The working end of the catheter further includes a guide wire lumen 42for accepting a guide wire 98. The tip of the guide wire 98 ispreferably rounded. The guide wire lumen 42 is preferably insulated soas to prevent or minimize any coupling effect the electrodes 66 may haveon the guide wire. The guide wire can be removed before the applicationof RF energy to the electrodes. The guide wire lumen can also allow forthe delivery or perfusion of medicant and cooling solution to thetreatment area during application of the RF energy.

FIG. 16 is a side view of the catheter of FIGS. 11, 12, and 13 beingdeployed from an antegrade approach to treat an incompetent valve. InFIG. 16, the leaflets are in contact with the bowable arms and RF energymay be applied just below them to the vein wall to reduce the diameterof the vein at the valve to restore valvular competency. FIGS. 17 and 18present another approach where the commissures are first shrunk (FIG.17) and then the catheter is used to impart RF energy to the leaflets,if needed (FIG. 18). As shown in the front view of FIG. 17, the bowableelectrodes 66 are expanded outward to treat the commissures on oppositesides of the vein simultaneously. The application of RF energy heats andshrinks the venous tissue at the commissures in order to restore valvecompetency. The application of RF energy can be halted, and the cathetermanipulated to treat the leaflets if necessary, by retracting thebowable electrodes toward the body of the catheter as shown in FIG. 18.The catheter may also be pushed forward so as to come into closerproximity to the valve. Such treatment allows valve leaflet shrinkage torestore the competency of the venous valve.

Another embodiment, shown in a side view in FIG. 19, is similar to thatshown in FIGS. 11, 12, and 13 except that only one pair of electrodes100 is included on the catheter 102. The electrodes 100 are a pair oflongitudinal electrodes located on one side of the catheter which can bebowed outwardly. The electrodes 100 can have the same construction asthe bowable electrodes described in connection with the embodimentillustrated in FIGS. 11, 12, and 13 for example. The operation of thisembodiment is similar to that described previously, except that each ofthe commissures would be treated one at a time. As previously describedand shown in FIG. 14, this catheter can be made in a manner to maintaina predetermined distance between the pairs of active electrodes despiteoutward bowing and diameter expansion.

Another embodiment, shown in plan view in FIG. 20 comprises a catheter103 that uses an asymmetrical balloon 104 to deflect the electrodes 106at the working end of the catheter to one side. The balloon 104 islocated on the side of the catheter opposite to the electrode pair. Whenthe balloon 104 is inflated, the opposite side of the working endaccommodating the longitudinal electrodes 106 is moved into appositionwith the venous tissue to be treated. After treating the dilated venoussection, the balloon can be deflated, and the catheter removed from thevasculature. It should be noted that the other mechanisms for deflectingthe working end of the catheter may be used. For example, a bendableactuation wire or strut may be used on one side of the catheter in orderto perform a function similar to that of the asymmetrical balloon.Although not shown, the catheter is similar in internal construction tothe previously discussed embodiments.

FIGS. 21 through 24 present an example of an application of thedirectional energy application catheter 103, shown in FIG. 20. In FIG.21, an incompetent valve taken along lines 2--2 of FIG. 1 is beingtreated at one commissure 30 by the catheter 103 of FIG. 20 having anelectrode pair 106 (not shown) and an inflated balloon 104 opposite theelectrode pair 106 to position the electrode pair in apposition with thecommissure 30. In FIG. 21, the electrode pair 106 of the catheter 103has been positioned by means of inflating the balloon 104 in appositionwith the opposite commissure 28. Finally, in FIG. 23, the electrodecatheter 103 has both electrodes 106 in apposition with one valveleaflet 32 to shrink the leaflet 32. Alternatively, apposition with onlythe commissure 28 or 30 may provide enough shrinkage of the vein so thatcontact with the leaflets 32 is not necessary.

The directional catheter shown in FIGS. 19 and 20 may also be used toreduce the size of or occlude an opening or ostium into a branch vein.Where such vein provides too great a flow into another vein, the ostiumof the branch vein can be reduced in size to decrease the flow oroccluded to terminate flow. In some cases, it is impractical to treatthe branch vein itself; therefore, occluding its ostium may improveconditions. In such a case, a catheter such as that shown in FIGS. 19and 20 may be used to heat the ostium or tissue adjacent the ostium toreduce its size. The electrodes would be positioned against the ostiumwall by a positioning device, such as the balloon shown in FIG. 20 orthe strut shown in FIG. 19, and energy applied to reduce the ostiumsize.

Referring now to FIG. 25, an alternate embodiment of a directionalenergy applying catheter is presented. In this embodiment, a catheter130 having an optical fiber diffusing tip 132 is used to directionallyapply energy to a selected vascular segment. As shown, an optical fiber134 is disposed within the catheter 130 and is connected at its distalend to a light diffusing device 136, such as a sapphire crystal, toallow diffusion of optical energy, such as that produced by a LASERconnected to the proximal end of the catheter. Additionally, thediffusing tip may have a reflector 138 to direct the optical energytoward the wall of the vein and away from the catheter lumen in whichthe optical fiber is located. Other light sources, such as a flash lampmay be used. A tip deflecting wire or strut 140 is shown in thisembodiment to be deployed for placing the optical energy radiating tip132 in apposition with the vein wall; however, other devices may be usedfor accurate placement of the energy source, such as a balloon shown inFIG. 20. The outer sleeve 142 of the catheter is slidable. Sliding ittoward the distal tip results in the strut 140 expanding and sliding thesleeve in the proximal direction results in the strut 140 contracting.

As can be readily ascertained from the disclosure herein, the surgicalprocedure of the present invention is accomplished without the need forprolonged hospitalization or post-operative recovery. The restoration ofvenous function is possible without the need for continued lifestylechanges, such as frequent leg elevation, the wearing of elastic supportstockings, or prolonged treatment of recurrent venous stasis ulcers.Moreover, the need for surgery of the arm and leg for transplantation ofarm veins into the leg would not be necessary.

Early treatment of venous disease could prevent more seriouscomplications such as ulceration, and valve damage caused bythrombophlebitis or thromboembolism. The cost of treatment andcomplications due to venous disease would be significantly reduced.There would be no need for extensive hospitalization for this procedure,and the need for subsequent treatment and hospitalization would also bereduced from what is currently needed. Furthermore, the minimallyinvasive nature of the disclosed methods would allow the medicalpractitioner to repair or treat several vein sections in a singleprocedure in a relatively short period of time.

It is to be understood that the type and dimensions of the catheter andelectrodes may be selected according to the size of the vein to betreated. Although the present invention has been described as treatingvenous insufficiency of the lower limb such as varicose veins in theleg, the present invention can be used to intraluminally treat venousinsufficiency in other areas of the body. For example, hemorrhoids maybe characterized as outpocketed varicose veins in the anal region.Traditional treatments include invasive surgery, elastic ring ligation,and the application of topical ointments. Shrinking the dilated veinsusing RF energy can be accomplished in accordance with the presentinvention. Specifically, the catheter and electrode combination isintroduced into the venous system, into the external iliac vein, theinternal iliac vein, then either the hemorrhoidal or the pudendal vein.The catheter then delivers the electrode to the site of the dilatedhemorrhoidal vein by this transvenous approach. Fluoroscopic techniquesor any other suitable technique such as pulse-echo ultrasound, aspreviously discussed, can be used to properly position the electrode atthe venous treatment site. The treatment site is preferably selected tobe at least two centimeters above the dentate line to minimize pain. Theelectrode applies RF energy at a suitable frequency to minimizedcoagulation for a sufficient amount of time to shrink, stiffen, andfixate the vein, yet maintain venous function or valvular competency.This intraluminal approach avoids the risks and morbidity associatedwith more invasive surgical techniques such as hemorrhoidectomy, whilesignificantly reducing reflux of blood in the area without necrosing orremoving the venous tissue.

Another area of venous insufficiency relates to erectile impotency ofthe penis. A significant number of all physically-induced cases ofimpotence result from excessive drainage of blood from the penile venoussystem. Venous-drainage-impotence can be treated using the presentinvention. Catheters having a sufficiently small diameter can be used todeliver the electrodes through the dorsal vein of the penile venoussystem to shrink this venous outflow path.. Fluoroscopic or ultrasoundtechniques can be used to properly position the electrode within theincompetent vein. RF energy or other radiant energy is applied from theelectrodes at a suitable frequency to shrink the surrounding venoustissue in order to reduce the excessive amount of drainage from thepenis while maintaining venous function or valvular competency. Theamount of shrinkage of the vein can be limited by the diameter of thecatheter itself, or the catheter or electrodes themselves can beexpanded to the appropriate size. Ligation of these veins should beavoided so as to allow for the proper drainage of blood from an engorgedpenis which is necessary for proper penile function.

Another area of venous insufficiency suitable for treatment inaccordance with the present invention involves esophageal varices.Varicose veins called esophageal varices can form in the venous systemalong the submucosa of the lower esophagus, and bleeding can occur fromthe swollen veins. Properly sized catheters can be used in accordancewith the present invention to deliver the electrodes to the site ofvenous insufficiency along the esophageal varices. Endovascular accessfor the catheter is preferably provided through the superior mesentericvein or portal vein to shrink the portal vein branches leading to thelower esophagus. Proper positioning of the electrode within the vein canbe confirmed using fluoroscopic or ultrasound techniques. The electrodesapply RF energy or other radiant energy at a suitable frequency toshrink the vein and reduce the swelling and transmission of high portalvenous pressure to the veins surrounding the esophagus.

While several particular forms of the invention have been illustratedand described, it will be apparent that various modifications can bemade without departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited, except asby the appended claims.

What is claimed:
 1. A method of applying energy to cause shrinkage of avein lumen, the method comprising the steps of:introducing a catheterhaving a working end with an energy application apparatus located at theworking end, to a treatment site in the vein lumen; positioning theenergy application apparatus adjacent the treatment site in the veinlumen; directionally emitting energy from the energy applicationapparatus to selectively heat the treatment site and cause shrinkage ofa selected area of the vein lumen at the treatment site; and terminatingthe emission of energy from the energy application apparatus aftercausing sufficient shrinkage of the vein lumen to restore valvularcompetency while maintaining venous patency.
 2. The method of claim 1further comprising the step of determining the occurrence of shrinkageof the vein using fluoroscopy.
 3. The method of claim 1 wherein the stepof positioning the energy application apparatus at the treatment sitefurther includes the step of placing the energy application apparatus ata commissure of a venous valve of the treatment site.
 4. The method ofclaim 3 further including the step of positioning the energy applicationapparatus adjacent leaflets of the valve, after the step of placing theenergy application apparatus at the commissure of the venous valve ofthe treatment site.
 5. The method of claim 1 wherein the step ofdirectionally emitting energy further includes the step of producing atleast two discrete RF fields at the working end of the catheter by theenergy application apparatus to directionally heat at least twoseparated venous sites at the treatment site simultaneously.
 6. Themethod of claim 1 wherein the step of directionally emitting energyfurther includes the step of producing a discrete RF field along aportion of the circumference of the catheter by the energy applicationapparatus to directionally heat the venous tissue.
 7. The method ofclaim 6 wherein the step of producing the discrete RF field includes thestep of positioning the catheter to treat the commissure of the venousvalve, and then the leaflets of the venous valve.
 8. The method of claim1 wherein the step for directionally emitting energy comprises the stepof passing radio frequency energy between a positive polarity electrodeand a negative polarity electrode to create an RF field along a portionof the catheter.
 9. The method of claim 1 wherein the step ofdirectionally emitting energy comprises the step of directionallyemitting optical energy to selectively heat the treatment site.
 10. Themethod of claim 9 wherein the step of directionally emitting opticalenergy comprises the further step of reflecting optical energy at theworking end of the catheter to create a directional emission of energyfor selectively heating the treatment site.
 11. The method of claim 1further comprising the step of palpating the vein into apposition withthe energy application apparatus of the catheter in the vein lumen. 12.The method of claim 1 further comprising the steps of locating theworking end of the catheter in apposition with the vein wall adjacent aselected commissure and directionally emitting energy to the vein wallto shrink the commissure.
 13. The method of claim 1 further comprisingthe step of expanding the energy application apparatus radially outwardfrom the working end and into apposition with the vein wall anddirectionally emitting energy to the vein wall to cause preferentialshrinkage of venous tissue at the wall.
 14. The method of claim 13wherein the step of expanding comprises the step of expanding at leasttwo pairs of electrodes from the working end into apposition with thevein wall, wherein each pair of electrodes comprises a discrete pair ofopposite polarity electrodes and the electrodes within each discretepair are arranged such that an electrode in one discrete pair isadjacent a like polarity electrode of the adjacent pair.
 15. The methodof claim 14 wherein the step of expanding comprises the step ofexpanding an even number of electrodes into apposition with the veinwall, wherein said even number comprises at least four, and wherein saideven number of electrodes are disposed in a plurality of discrete pairsof opposite polarity electrodes, said electrodes in each discrete pairbeing arranged such that an electrode in one discrete pair is adjacent alike polarity electrode of an adjacent pair.
 16. The method of claim 1further comprising the step of determining the occurrence of shrinkageof the vein using ultrasonographic imaging.
 17. The method of claim 1wherein the step of positioning the energy application apparatus at thetreatment site further includes the step of placing the energyapplication apparatus at an ostium and applying energy to reduce thesize of the ostium.
 18. A method of applying energy to cause theshrinkage of a vein to restore valvular competency, the methodcomprising the steps of:introducing a catheter having a working end andat least two electrodes located at the working end, to a treatment sitein the vein; positioning the at least two electrodes adjacent venoustissue at the treatment site in the vein; applying high frequency energyfrom the electrodes to heat the treatment site and cause a reduction inthe size of the vein; and terminating the application of energy from theelectrodes after the size of the vein is reduced so that valvularcompetency is restored and patency of the vein is maintained.
 19. Themethod of claim 18 further comprising the step of determining theoccurrence of shrinkage of the vein using fluoroscopy.
 20. The method ofclaim 18 further comprising the step of determining the occurrence ofshrinkage of the vein using ultrasonographic imaging.
 21. The method ofclaim 18 wherein the step of applying high frequency energy furtherincludes the step of applying radio frequency energy between the atleast two electrodes.
 22. The method of claim 18 wherein the step ofemitting high frequency energy further includes the step of producing adiscrete RF field along a portion of the circumference of the catheterto directionally heat the venous tissue.
 23. The method of claim 22wherein the step of producing the discrete RF field includes the step ofpositioning the catheter to treat the commissures of the venous valve,and then the leaflets of the venous valve.
 24. The method of claim 18wherein the step of positioning the at least two electrodes at thetreatment site further includes the step of placing the at least twoelectrodes at a commissure of the venous valve of the treatment site.25. The method of claim 24 further including the step of placing theelectrodes adjacent the leaflets of the valve after the step of placingthe electrodes at the commissure of the venous valve of the treatmentsite.
 26. The method of claim 18 wherein the step of emitting energyfurther includes the step of producing at least two discrete RF fieldsalong the circumference of the catheter to directionally heat the venoustissue so that both commissures of the venous valve at the treatmentsite can be treated simultaneously.
 27. The method of claim 18 furthercomprising the step of extending the electrodes away from the catheterto increase the effective diameter of the catheter.
 28. The method ofclaim 27 further comprising the step of deploying an expandable membercoupled to the working end to selectively position the two electrodesagainst selected venous tissue.
 29. The method of claim 28 wherein thestep of extending comprises the step of expanding at least two pairs ofelectrodes from the working end into apposition with the vein wall,wherein each pair of electrodes comprises a discrete pair of oppositepolarity electrodes and the electrodes within each discrete pair arearranged such that an electrode in one discrete pair is adjacent a likepolarity electrode of the adjacent pair.
 30. The method of claim 29wherein the step of expanding comprises the step of expanding an evennumber of electrodes into apposition with the vein wall, wherein saideven number comprises at least four, and wherein said even number ofelectrodes are disposed in a plurality of discrete pairs of oppositepolarity electrodes, said electrodes in each discrete pair beingarranged such that an electrode in one discrete pair is adjacent a likepolarity electrode of an adjacent pair.
 31. The method of claim 18further comprising the step of palpating the vein into apposition withthe electrodes of the catheter in the vein lumen.
 32. The method ofclaim 18 further comprising the steps of locating the working end of thecatheter in apposition with the vein wall adjacent a selected commissureand directionally emitting energy to the vein wall to shrink thecommissure.
 33. The method of claim 18 wherein the step of positioningthe energy application apparatus at the treatment site further includesthe step of placing the energy application apparatus at an ostium andapplying energy to reduce the size of the ostium.